Electrical dental engine



(No Model.)

' a Sheets'eSheet 1. R0. PRIESTLY.I BLEG'TRIGAL DENTAL ENGINE. No. 549,464. Patented Nov. 5, 1895.

$5 a i a 5' WITNESSES: Z [7L INVENTQR F C. Pr/esf/y.

ANDREW B GRAHAM. PHOTO-HMO. WAS!" REIGN, D11

ATTORNEY (No Model.) 3 SheetsSheet 2. F. O. PRIESTLY.

BLEGTRIGAL DENTAL ENGINE.

No. 549,464. Patented Nov. 5,1895. 4

WITNESSES: INVENTOR FC. Pr/esf/y.

@441. 3: m @XQ ATTORNEY AN DREW 8.6RAHAM, PHOIc-umm wnsm N GTON. D.c

Nd Model.) 3 Sheets-Sheet 3.

. P. 0. PRIESTLY. ELECTRICAL DENTAL ENGINE.

No. 549,464. Patented Nov.- 5, 1895.

IN VEN T 0R WCF F/eST/ ATTORNEY WITNESSES AN DREW 8.6MHAM. PHOTO-LITHQWASHI N GTON v D I.v

UNITED STATES PATENT OFFICE.

FRANK C. PRIESTLY, OF DENVER, COLORADO.

ELECTRICAL DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 549,464, dated November 5, 1895.

A li ati n filed February 12, 1895. Serial No. 538,085. No model.)

To aZZ whom it may concern.- I

Be it known that I, FRANK C. PRIESTLY, a citizen of the United States of America, residing at Denver, in the county of Arapahoe and State of Colorado, have invented certain new and useful Improvements in Electrical Dental Engines; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specification. I

My invention relates to improvements in electrical dental engines; and it consists of the features, arrangements, and combinations hereinafter described and claimed, all of which will be fully understood by reference to the accompanying drawings, in which is illustrated an embodiment thereof.

In the drawings, Figure 1 is an elevation of the device. Fig. 2 is a vertical section taken through the motor, the motorstand, and the rheostat, the armature, the field-magnets, and the resistance-coils being shown in elevation. Fig. 3 is an underneath view of the stand, illustrating the controlling mechanism of the rheostat. Fig. 4 is a horizontal section taken through the motor on the line :2: :0, Fig. 2. Fig. 5 is a diagrammatic View illustrating the circuit of the electrical plugger. Fig. (5 is a section taken on the line y 3 Fig. 2. Fig. 7 is an enlarged section taken through the clutch or brake mechanism. Fig. 8 illus trates the hinge-j oint of the upper arm. This is a view, partly in section, taken on the line 2, Fig. 7. Fig. 9 is a longitudinal section taken through the electrical plugger. Fig. 10 is a view taken through the rheostat-controlling mechanism on the line 10 10, Fig. 3. Fig. 11 is a diagrammatic view illustrating the circuit. Fig. 12 is a diagrammatic view illustrating the plugger-c-ircuit.

In the drawings sections of coils or solenoids are hatched and sections of insulating material are generally indicated by dark hatching.

Similar reference characters indicating corresponding parts in the several views, let the numeral 5 designate ahollow standard formed largest at the base and provided with feet adapted to support it in a suitable position. To the top of this standard is attached the stationary shell (3 of the motor inclosing the stationary field-magnets 7 and the armature 8 surrounding said magnets. The armatureframe 8 and the magnet-frame 7 are mounted on a shaft 9, made fast to'the shell 6. The armature-frame engages one extremity of the shaft and the magnet-frame is located be tween the armature frame and the shell. The commutator 10 is attached to the inner surface of the armature-frame, While to the outer surface of said frame is attached a pulley 12. The commutator comprises an insulating-base 10, attached directly to the armature-frame, and a series of segmental contacts 10 attached to the innner surface of said base.

The brushes 30 and 31 engaging the commutator are located in tubular holders 30, carrying coil springs 30"", which force the brushes to contact with the commutators segments. These brush-holders are inserted in the magnet-frame between the magnets and protrude through the shell of the motor, whereby they are accessible from the outside.

IVithin the base of the standard 5 and so located as to clear the surface upon which the device stands is attached an insulating-plate 13. To the upper surface of this plate is attached a rod 14, projecting upward into the space inclosed by the stand. To the top of this rod is attached another plate 15. Between the plates 13' and 15 and attached thereto and supported thereby are a number of resistance-coils 16. To the under surface of the insulating-base 13 are attached a number of contact-plates 1 7,electrioally connected with the respective resistance-coils, which are connected with each other in series.

To the under surface of the plate 13 is pivoted an arm 18, one extremity of which is adapted to engage the separated contacts 17, which, of course, are insulated from each other. The other extremity of the arm 18 protrudes from the base of the standard,whereby it is adapted to be shifted by the foot of the operator or person using the device. This arm is composed of conducting materia1,preferably metal, and is electrically connected with one pole of the electrical source 19,(see Fig. 11,) whereby said arm forms an essential part of the circuit.

In a groove formed in the plate 13 is located an insulating bar 20. This bar occupies a transverse position with reference to the arm 18 and is located immediately above the latter. The bar is provided with offsets 20 and 20 located on either side of the arm and in the path thereof, whereby, after a certain movement of the arm, the latter engages an offset and shifts the position of the bar,which carries two metallic contacts 21 and 22,which are adapted to engage stationary contacts 23, 24 and 25, made fast to the plate 13. Assuming that the contacts 21 and 22 are in engagement with the contacts 23 and 24,respectively, and that the arm 18 engages the contact 17 farthest to the left in Fig. 11, and referring specially to this figure, the current may be said to pass from the source 19 through a conductor 26 to the arm 18, thence to the contact 17, thence through all of the resistance-coils 16 to the contact 17 farthest to the right in Fig. 11, thence m'a conductors 27 and 28 to the contacts 22 and 24, thence UiCt a conductor 29 to a brush 30, thence to the commutator 10, thence through the armature-coils S and to the other brush 31,engaging the commutator, thence m the conductor 32 to the contact 23, thence to the contact 21, thence m a conductor to the coils of the field-magnets 7, thence via a conductor 34 to the coils of a magnet 35,forming a part of the instantaneous brake-mechanism hereinafter described, and thence m'a a conductor 36 to the other pole of the electrical source.

In the drawings (see Figs. 3 and 11) three contacts 17 are shown. It is evident that if the contact end of the arm 18 be shifted to engagement with the next contact 17 toward the right, referring to Fig. 11, one or more of the resistance-coils 16 will be cut out of the circuit, and when the arm 18 engages the contact 17 farthest to the right all the resistance-coils 16 of the rheostat will be cut out and the current will pass directly to the conductor 28. If, when the arm 18 is in the position last assumed, its contact extremity be moved farther to the right, it will engage an insulating-segment 37, when the circuit will be broken and the motor stopped. WVhen the arm 18 is in this position, it is in engagement with the offset 20 of the bar 20. Now if it is desired to reverse the action of the motor or the movement of the armature the contact extremity of the arm 18 is shifted farther to the right, whereby the bar 20 is moved sufficiently to disengage the contact 21 from the contact 23 and the contact 22 from the contact 24 and cause these contacts 21 and 22 to engage the contacts 24 and 25, respectively, the contact extremity of the arm 18 being at the same time brought to engagement with a metallic contact 17, connected With the contact 22 by the con ductor 28. In this case the path of the ourrent will be as follows: from the source 19 to the contact 22 cm the circuit elements 26 18 17 and the conductor 28, thence to the contact 25, thence via the conductor 32 to the brush 31 of the motor, thence via the armature-coils 8 to the brush 30, thence via the conductor 29 to the contact 24, thence to the contact 21, thence via the conductor 33 to the coils 7 of the field-magnets, thence m the conductor 34 to the other pole of the source cm the coil 35. Hence the rotation of the armature will be reversed, since the direction of the current through the coils of the armature is reversed.

Attached to the top of the shell or casing of the motor and extending upward there from is a hollow rod 40. To the top of this rod is made fast a horizontal spindle 41, composed of soft iron or other magnetic material possessing the proper coefficient of magnetic permeability. This spindle has a double function. It forms the hinge-pin forahollow rod 42, extending upward from the spindle, and it also serves as the core for a magnet, having coils 35 lying in the motor-circuit, as heretofore explained. The spindle 41 also carries a ring 43, composed of magnetic material and having pins 43*" engaging counterpart recesses formed in the head or enlarged extremity of the spindle or core. Several of these pins are surrounded by coil-springs 44, engaging the ring and having a tendency to move it away from the core end. On the side of the ring opposite the pins 43, are formed projections or short pins 43 adapted to engage counterpart recesses formed on the inner surface of the pulley 12. lVhen the projections 43 engage the counterpart recesses in the pulley, the latter is locked from rotation. \V hen, however, the coils 35 of the magnet mounted on the spindle are in the circuit, the core 41 is magnetized and the ring (which is allowed sufficient movement for the purpose) drawn toward the coils 35 and the pulley released. The ring occupies this position as long as the coils are in circuit. As soon, however, as the current is cut off, the core 41 is demagnetized and the ring is immediately actuated by the springs, whereby the projections 43 are made to engage the recesses in the pulley 52, thus forming a clutch and instantly stopping the pulley. As soon, however, as the magnet is again energized, the ring 43 is again attracted and the pulley released. This instantaneous clutch or quick-stop mechanism is for use in connecting with the rotatable flexible shaft 44, adapted to carry a dental tool and well known in the art. This shaft 44, as shown in the drawings, (see Fig. 1,) is mounted on the upper extremity of the hinged rod 42 and provided with a fast pulley 45, which is connected by a belt 46 with the pulley 52, the last-named pulley being in turn connected with the pulley 12 on the armature of the motor by a belt 47.

The electrical plugger is provided with an insulating-casing 50, having its extremities interiorly threaded to receive the apertured metal tips 51 and 53. WVithin the casing are located the insulating-rings 54, 55, 56, and 57,

' surrounding the hollow stationary core 58,

in which is located the movable bar 59, composed of soft iron or other suitable magnetic material. Surrounding the hollow core 58 and located between the insulating-rings 54L and 55 is located a solenoid 60. Between the insulating-rings 55 and 56 is located a metallic contact-ring 61 and between the insulating-rings 56 and 57 is located a metallic contact-ring 62. These rings 61 and 62 are insulated from the hollow core and adapted to be connected by a sliding metal plate 63, to which is attached a small insulating knob or pin 64, engaging a slot 65, formed in the shell or casing 50 and protruding therefrom. A conductor 66 is connected with the contactring 62, while a conductor 67 connects the ring 61 with the solenoid 60. Another conduct-or 67 leads directly to the solenoid without engaging intermediate contacts after entering the casing 50. The conductor 67 of the plugger is attached directly to the brush 31 of the motor. The conductor 66 is connected with a stationary auxiliary brush 68, adapted to alternately make and break the plugger-circuit as the motor-armature rotates with its commutator. This may be accomplished by having one or more contacts 69 attached to the commutator and so located that the auxiliary brush is in the path thereof.

The auxiliary brush 68 should be so adjusted that it may be moved out of the path of the contact 69 when it is desired to operate the plugger. To this end the brush comprises an arm having a yielding extremity adapted to engage the contact 69, while its opposite extremity is composed of non-conducting material, whereby the arm may be grasped and shifted at pleasure.

If it is desired to close the circuit but once during each rotation of the armature, only one contact 69 may be employed. It is evident that the number of these contacts may be regulated at will and will be determined according to the rapidity with which it is desired to reciprocate the movable bar of the plugger. The forward extremity of this bar carries the tool 70, while to the rear extremity of the bar is made fast a stem 71, carrying a stop 73. This stem engages an aperture formed in a stationary cross-head or guide 7 2. Between the guide 72 and the stop 7 3 is located a coil-spring 74, surrounding the stem 71. This spring is of sufficient strength to hold the bar normally at its backward limit of movement.

Every time the circuit is closed by the engagement of the auxiliary brush with the special contact attached to the commutator of the motor the solenoid will be energized and the bar 59 carried forward by the induced magnetic force. As soon as the circuit is opened or broken by the disengagement of said part, the solenoid is de-energized, the bar released and drawn backward by the spring 7%.

l/Vhen the plugger-circuit is closed, the current may be said to pass (see Fig. 12) from the brush 31 via the conductor 67 to the solenoid 60, thence m the conductor 67 to the ring 61, thence cm the slide 63 to the ring 62, thence can the conductor 66 to the brush 68, and thence to the contact 69, attached to the commutator.

From the foregoing description the operation of the device will be readily understood. The conductors leading to the plugger pass out of the rod 40 through an aperture 40, formed just below the instantaneous brake or clutch mechanism. WVhen the plugger is not in use, the circuit is opened by adjusting the slide 63, through the instrumentality of the knob 65, so that said plate shall engage but one of the rings 61 62.

In using the flexible rotatable shaft 44 the speed of the motor is regulated at will through the medium of the pivoted arm 18 and the rheostat mechanism.

Having thus described my invention, what I claim is 1. The combination with the motor and circuit, of the hollow stand upon which the motor is mounted, and the rheostat interposed in the circuit and comprising a plate attached to the bottom of the stand and connected therewith contacts attached to the plate, a pivoted arm engaging said contacts and protruding from the stand whereby it may be operated from the outside, a bar slidingly at tached to the plate, contact pieces attached to the bar and normally engaging the contacts on the plate, an auxiliary contact on the plate normally idle but lying in the path of one of the contact pieces on the bar, the bar and the pivoted arm being so connected that the movement of the latter actuates the former, substantially as described.

2. In an electrical dental engine, the combination with the motor, of the plugger com prising a shell, a hollow core, a reciprocating bar, a spring for imparting motion to the bar in one direction, a solenoid for imparting motion to the bar in the opposite direction, a conductor leading from one of the commutator brushes to the solenoid, an auxiliary brush so arranged that the circuit in which it lies is alternately made and broken as the armature rotates, and a conductor leading from said auxiliary brush and electrically connected with the solenoid, substantially as described.

3. In an electrical dental engine, the combination with the motor, of the plugger comprising a reciprocating bar, a spring for imparting motion to the bar in one direction, a solenoid for imparting motion. to the bar in the opposite direction. and lying in the motor circuit, and means for alternately making and breaking the solenoid circuit at the motor as the armature rotates, substantially as described.

4. In an electrical dental engine, the combination with the motor, of a plugger comprising a shell incasing a reciprocative bar, a spring for moving the bar in one direction, a solenoid lying in the motor circuit for moving the bar in the opposite direction, means attached to the motor for alternately and automatically making and breaking the solenoid circuit as the armature rotates, and means attached to the plugger for making and breaking the circuit at the will of the operator, substantially as described.

5. In an electrical dental engine, the combination with the motor mounted upon a stand, of an upright rod attached to the mo tor casing, a spindle mounted on said rod and having an enlarged head provided with recesses, a pulley made fast to said spindle, a belt or similar connection between said pulley and the pulley on the armature, a ring slidingly mounted on the spindle, but locked from rotation, said ring having projections on one face adapted to engage counterpart recesses formed in the adjacent face of the pulley, the other face of the ring having pins adapted to enter the recesses in .the head of the spindle, springs surrounding several of said pins and engaging the bottom of their corresponding recesses and normally holding the ring in the locking position, an electromagnet of which the spindle forms the core, the arrangement being such that when the magnet is energized, the ring is attracted and the pulley released, and a rod hinged on the spindle and carrying the tool to be operated, substantially as described.

6. In an electrical dental engine, the com bination with the motor and stand, of an upright rod attached to the motor casing, a spindle journaled in the outer extremity of the rod, a pulley fast on the spindle, an arm hinged on said spindle, a shaft journaled in the outer extremity of the arm and carrying a pulley, arotatable tool attached to the shaft, a suitable connection between the spindle on the shaft and the pulley 011 the spindle, and a suitable connection between the spindle and the armature shaft, whereby the rotation of the latter actuates the former, substantially as described.

In testimony whereof I afliX my signature in the presence of two witnesses.

FRANK C. PRIESTLY. Witnesses:

CHAS. E. DAwsoN, B. W. WIsEBAR'r. 

